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A036091
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Centered cube numbers: (n+1)^13+n^13.
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4
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1, 8193, 1602515, 68703187, 1287811989, 14281397141, 109949704423, 646644824295, 3091621642217, 12541865828329, 44522712143931, 141515917523003, 409868311971325, 1096589879846397, 2739909841613519
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| Never prime, as a(n) = (2n + 1) * (n^12 + 6n^11 + 36n^10 + 125n^9 + 295n^8 + 496n^7 + 610n^6 + 553n^5 + 367n^4 + 174n^3 + 56n^2 + 11n + 1). Semiprime for n in {1, 8, 15, 21, 86, 135, 141, 249, 260, 278, 323, 326, 363, ...}. [Jonathan Vos Post, Aug 26 2011]
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REFERENCES
| B. K. Teo and N. J. A. Sloane, Magic numbers in polygonal and polyhedral clusters, Inorgan. Chem. 24 (1985), 4545-4558.
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LINKS
| Vincenzo Librandi, Table of n, a(n) for n = 0..10000
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PROG
| (MAGMA) [(n+1)^13+n^13: n in [0..20]]; // Vincenzo Librandi, Aug 27 2011
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CROSSREFS
| Cf. A036085, A036087, A036088, A036089, A036090.
Sequence in context: A035908 A017689 A013961 * A181134 A168346 A045060
Adjacent sequences: A036088 A036089 A036090 * A036092 A036093 A036094
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KEYWORD
| nonn
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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